Slide-valve gear of steam-engines



UNITED STATES PATENT FFICE,

ELIJAH 'ARE, OF SOUTH BOSTON, MASSAOHUSETTS.

SLIDE-VALVE GEAR OF STEAM-ENGINES.

Specification of Letters Patent No. 22,318, dated December 14, 1858.

To all 'whom 'Lt may concern:

Be it known that I, ELIJAH IVARE, of South Boston, in the county of Sulfolk and State of Massachusetts, have invented a new and Improved Slide-Valve Gear for Locomotives and other Steam-Engines; and I do hereby decla-re that the following is a full, clear, and exact description of the same, reference being had to the accompanying draWings, forming part of this specfication, in Which- Figure l, is a side view of my valve-gear. Fig. 2, is a plan of the same.

Similar letters of reference indicate corresponding parts in both figures.

This invention consists in a certain combination of mechanical devices for effecting the connection between the slide valve and an eccent-ric on the crank shaft, Whereby a single eccentric fastened permanently on the shaft is made to operate one valve to run an engine in either direction and to give.

different lengths of stroke and different degrees of lead to the valve, to effect the regulation of the engine, thus performing, With one eccentric, What in locomotive engines, With ordinary valve-gear, requires three eccentrics to each cylinder.

To enable others skilled in the art to make and use my invention, I Will proceed to describe its construction and operation.

A, is the crank-shaft; B, is the eccentric, Secured permanently to the shaft in a position coinciding With that of the crank.

D, is the eccentric rod, Which is made very short; and E G, E G, are What I call fulcrum-plates, tWo in number, fitted to turn easily on the crank shaft, one on each side of the eccent-ric, and secured together by a pin b, passing through the eXtremities of their arms E, E. These plates are connected at the pin b, by a rod F, With a pin a, in the extremity of the eccentric rod. The length of the eccentric rod from the center of the eccentric to the center of the pin a. and the distance from the center of the shaft to the center of the pin I), are equal, and the length of the rod F, is such that the center line of the eccentric rod and center line of the arms E, E, are at a right-angle to each other When the center of the eccentric is in line With the center of the shaft and center of pin b.

I-I, is a Circular frame encircling the Crank-shaft and eccentric, and containing an are-formed slot c, extending a little more than half Way around, said slot being described With a radius equal to the distance of the pin b, from the center of the crankshaft. The said 'frame has also twoI projecting arms I, I', of equal length, to Which are firmly Secured a plate J, Which contains an are-'formed slot (i, Which receives a pin e, at the end of a rod vK, thatis connected by a slot and pin connection g, h, With an arm f, of the rock-shaft L, from Which the slide valve M, derives motion, the pin h, being fast in the rod K. The slide valve is to be an ordinary lap-valve. The slot (Z, is described With the radius eg, h. The connecting-pin ha, is fitted to work in a slot i, in a stationary bar N, constituting a portion of the engine framing, and the same bar contains a straight slot 7', Which constitutes a guide to a pin in, that is secured to the frame H. The slots j, and i, are in line With each other and a plane drawn through their centers Will pass through the axis of the shaftand midWay between the arms I, I. The frame H, H, is held perpendicular to the shaft by means of the plates E G, E G, whose arms G, G, have no other duty to do. The pin b, in the fulcrum-plates, Which may be termed the fulcrum-pin, is connected by a rod P, and pin 41-, With one end of a lever Q, arranged on a fiXed fulcrum Z. The opposite end of the lever Q, is connected by a pin m, rod R, and pin 7), With an arm S, on the end of the valve rod K, Which is extended beyond the pin h, tiihich Works the valve rock-shaft.

The rotation of the shaft A, in the operation of the engine, produces no movement of the fulcrum-pin b, or fulcrum-plates E G, but the said pin and plates are held stationary by the rod P, lever Q, and rod R, and the said pin, becomes a fulcrum upon Which, by the operation of the'eccentric, the frame H, with its attached plate J, are caused to rock. By the above rocking motion. the rod K, has imparted to it a reciprocating motion by Which the valve rockshaft L, and valve M are operated. The stroke of the valve is greater or less as the rod K, is farther from or nearer to that end of the slot (Z, Which is nearer the pin Z), and as the stroke is increased the lead is diminished, and Vice versa, and hence, the position of the rod K, governs the motion of the engine in two Ways, viz: by varying the stroke and varying the lead. Suitable hand gear is intended to be provided to shift the rod K,

in the slot d, but it is not necessary to show it to illustra-te what I consider my invention.

Fig. 1, represents the valve-gear set for rotating in the direction of the arrow shown upon the shaft in Fig. l. To reverse the motion, the fulcrum plates have to be turned a quarter revolution on the shaft, and the eccentric-rod a corresponding distance on the eccentric, in the direction of the arrow shown on it in Fig. l, to change the position of the fulcrum b, to that extent, thus taking it from opposite the arm I, of the frame H, to opposite the arm Il. To provide for this change of position the arm S, on the valve rod K, is inade capable of turning on a pin q, Secured in the rod so that it can be brought down to the position shown in Fig. l, or turned up to the reverse position, and be secured in either position by a pin s, inserted through one of two holes 1", 1'1, in the arm, and a hole in the end of the rod K. By removing the pin s, from the hole r, in which it is shown in Fig. 1, and turning the arm. S, upward far enough to permt the insertion of the pin through the hole 711, and the same hole in theirod K, the rod R, is caused to draw up the attached end of the lever Q, and the said lever, by means of the rod P, draws down the fulcrum-pin b, in the slot 0, of the frame H,

and carries around the fulcrum-plates and the eccentric rod the required distance, and when the pin s, is inserted the fulcrum-pin b, becomes stationary. VVhen the engine is thus reversed, the adjustment to vary the stroke of the valve is the reverse of what it was before, the pin e, requiring to be raised in the slot d, to give the valve more motion, and vice versa. The lead of the valve is also reversed, but it still increases as the stroke of the valve is reduced.

The shifting of the fulcrum-plates may be etfected by other and perhaps more convenient means than those above described.

VVhat I claim as my invention and desire to secure by Letters Patent, is

The combination of the single eccentric, having a short eccentric-rod D, the fulcrumplates E G, carrying a fulcrum-pin b, having a connection with the short eccentric rod, the slotted frame H, receiving the fulcrum-pin and a pin on the eccentric rod, and the slotted plate J, receiving a pin e, or its equivalent attached to a rod connected with the valve, the whole being applied to operate substantially as herein set fort-h.

ELIJAH lVARE.

litnesses L. C. WARE,

lJVILLIAM SIIAW. 

